Multiple myeloma metabolism - a treasure trove of therapeutic targets?

Multiple myeloma is an incurable cancer of plasma cells that is predominantly located in the bone marrow. Multiple myeloma cells are characterized by distinctive biological features that are intricately linked to their core function, the assembly and secretion of large amounts of antibodies, and their diverse interactions with the bone marrow microenvironment. Here, we provide a concise and introductory discussion of major metabolic hallmarks of plasma cells and myeloma cells, their roles in myeloma development and progression, and how they could be exploited for therapeutic purposes. We review the role of glucose consumption and catabolism, assess the dependency on glutamine to support key metabolic processes, and consider metabolic adaptations in drug-resistant myeloma cells. Finally, we examine the complex metabolic effects of proteasome inhibitors on myeloma cells and the extracellular matrix, and we explore the complex relationship between myeloma cells and bone marrow adipocytes

MUKtwelve protocol: a phase II randomised, controlled, open, parallel group, multicentre trial of selinexor, cyclophosphamide and prednisolone (SCP) versus cyclophosphamide and prednisolone (CP) in patients with relapsed or refractory multiple myeloma.

INTRODUCTION: Multiple myeloma is a malignancy of plasma cells with around 6000 new cases per year in the UK. Cyclophosphamide plus prednisolone is considered a standard of care for disease and symptom control in the advanced relapsed or refractory myeloma setting within the UK NHS. The selective nuclear export inhibitor, selinexor, has been relatively well tolerated in previous clinical trials and offers promise when used in combination with a wide range of other anti-cancer treatments. Here, we investigate if the addition of selinexor can improve responses to cyclophosphamide plus prednisolone without adding prohibitive toxicity. METHODS AND ANALYSIS: MUKtwelve is a UK-based, randomised, controlled, open, parallel group, multicentre phase II trial designed to evaluate clinical efficacy of selinexor in combination with cyclophosphamide and prednisolone (SCP) in patients with relapsed or refractory multiple myeloma. A calibration arm will receive cyclophosphamide and prednisolone alone (CP). Participants who experience disease progression on the CP arm may, if eligible, receive SCP.The MUKtwelve trial results will be the first to assess clinical efficacy of selinexor with low-dose CP in relapsed/refractory multiple myeloma. It is widely accepted that the relapsing-remitting nature of the disease is accompanied by cellular changes that often result in the requirement for novel agents and drug combinations to regain disease control. Patients also often experience cumulative toxicities throughout their treatments, limiting the treatment intensity that can be given at relapse. Thus, there is a need for novel effective combination therapies with acceptable toxicity profiles. ETHICS AND DISSEMINATION: Ethics approval is obtained. Results will be submitted for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ISRCTN15028850

Differential regulation of human bone marrow mesenchymal stromal cell chondrogenesis by hypoxia inducible factor-1α hydroxylase inhibitors

The transcriptional profile induced by hypoxia plays important roles in the chondrogenic differentiation of marrow stromal/stem cells (MSC) and is mediated by the Hypoxia Inducible Factor complex. However, various compounds can also stabilise HIF's oxygen-responsive element, HIF-1α, at normoxia and mimic many hypoxia-induced cellular responses. Such compounds may prove efficacious in cartilage tissue engineering, where microenvironmental cues may mediate functional tissue formation. Here, we investigated three HIF stabilising compounds, which each have distinct mechanisms of action, to understand how they differentially influenced the chondrogenesis of human bone marrow-derived MSC (hBM-MSC) in vitro. hBM-MSCs were chondrogenically-induced in TGF-β3 -containing media in the presence of HIF-stabilising compounds. HIF-1α stabilisation was assessed by HIF-1α immunofluorescence staining, expression of HIF target and articular chondrocyte specific genes by qPCR, and cartilage-like extracellular matrix (ECM) production by immunofluorescence and histochemical staining. We demonstrate that all three compounds induced similar levels of HIF-1α nuclear localisation. However, whilst the 2-oxoglutarate analogue Dimethyloxalylglycine (DMOG) promoted upregulation of a selection of HIF target genes, Desferrioxamine (DFX) and Cobalt Chloride (CoCl2 ), compounds that chelate or compete with Fe2+ , respectively, did not. Moreover, DMOG induced a more chondrogenic transcriptional profile, which was abolished by Acriflavine, an inhibitor of HIF-1α-HIF-β binding, whilst the chondrogenic effects of DFX and CoCl2 were more limited. Together, these data suggest that HIF-1α function during hBM-MSC chondrogenesis may be regulated by mechanisms with a greater dependence on 2-oxoglutarate than Fe2+ availability. These results may have important implications for understanding cartilage disease and developing targeted therapies for cartilage repair. This article is protected by copyright. All rights reserved

Differential Regulation of Human Bone Marrow Mesenchymal Stromal Cell Chondrogenesis by Hypoxia Inducible Factor-1α Hydroxylase Inhibitors

The transcriptional profile induced by hypoxia plays important roles in the chondrogenic differentiation of marrow stromal/stem cells (MSC) and is mediated by the hypoxia inducible factor (HIF) complex. However, various compounds can also stabilize HIF's oxygen-responsive element, HIF-1α, at normoxia and mimic many hypoxia-induced cellular responses. Such compounds may prove efficacious in cartilage tissue engineering, where microenvironmental cues may mediate functional tissue formation. Here, we investigated three HIF-stabilizing compounds, which each have distinct mechanisms of action, to understand how they differentially influenced the chondrogenesis of human bone marrow-derived MSC (hBM-MSC) in vitro. hBM-MSCs were chondrogenically-induced in transforming growth factor-β3-containing media in the presence of HIF-stabilizing compounds. HIF-1α stabilization was assessed by HIF-1α immunofluorescence staining, expression of HIF target and articular chondrocyte specific genes by quantitative polymerase chain reaction, and cartilage-like extracellular matrix production by immunofluorescence and histochemical staining. We demonstrate that all three compounds induced similar levels of HIF-1α nuclear localization. However, while the 2-oxoglutarate analog dimethyloxalylglycine (DMOG) promoted upregulation of a selection of HIF target genes, desferrioxamine (DFX) and cobalt chloride (CoCl2 ), compounds that chelate or compete with divalent iron (Fe2+ ), respectively, did not. Moreover, DMOG induced a more chondrogenic transcriptional profile, which was abolished by Acriflavine, an inhibitor of HIF-1α-HIF-β binding, while the chondrogenic effects of DFX and CoCl2 were more limited. Together, these data suggest that HIF-1α function during hBM-MSC chondrogenesis may be regulated by mechanisms with a greater dependence on 2-oxoglutarate than Fe2+ availability. These results may have important implications for understanding cartilage disease and developing targeted therapies for cartilage repair. Stem Cells 2018; 00:000-000

The MUK eight protocol: a randomised phase II trial of cyclophosphamide and dexamethasone in combination with ixazomib, in relapsed or refractory multiple myeloma (RRMM) patients who have relapsed after treatment with thalidomide, lenalidomide and a proteasome inhibitor

Background Multiple myeloma is a plasma cell tumour with approximately 5500 new cases in the UK each year. Ixazomib is a next generation inhibitor of the 20S proteasome and is thought to be an effective treatment for those who have relapsed from bortezomib. The combination of cyclophosphamide and dexamethasone (CD) is a recognised treatment option for patients with relapsed refractory multiple myeloma (RRMM) who have relapsed after treatment with bortezomib and lenalidomide, whilst also often being combined with newer proteasome inhibitors. The most apparent combination for ixazomib is therefore with CD. Methods MUK eight is a randomised, controlled, open, parallel group, multi-centre phase II trial that will recruit patients with RRMM who have relapsed after treatment with thalidomide, lenalidomide, and a proteasome inhibitor. The primary objective of the trial is to evaluate whether ixazomib in combination with cyclophosphamide and dexamethasone (ICD) has improved clinical activity compared to CD in terms of progression-free survival (PFS). Secondary objectives include comparing toxicity profiles and the activity and cost-effectiveness of both treatments. Since opening, the trial has been amended to allow all participants who experience disease progression (as per the IMWG criteria) on the CD arm to subsequently switch to receive ICD treatment, once progression has been confirmed with two clinical members of the Trial Management Group (TMG). This ‘switch’ phase of the study is exploratory and will assess second progression-free survival measured from randomisation to second disease progression (PFS2) and progression-free survival from the point of switching to second disease progression (PFS Switch) in participants who switch from CD to ICD treatment. Discussion Development of ixazomib offers the opportunity to further investigate the value of proteasome inhibition through oral administration in the treatment of RRMM. Previous studies investigating the safety and efficacy of ICD in patients with RRMM demonstrate a toxicity profile consistent with ixazomib in combination with lenalidomide and dexamethasone, whilst the combination showed possible activity in RRMM patients. Further investigation of the anti-tumour effect of this drug in RRMM patients is therefore warranted, especially since no trials comparing CD with ICD have been completed at present. Trial registration ISRCTN number: ISRCTN58227268. Registered on 26 August 2015

Cardiovascular adverse events in modern myeloma therapy - incidence and risks. A review from European Myeloma Network (EMN) and Italian Society of Arterial Hypertension (SIIA)

Cardiovascular disease in myeloma patients may derive from factors unrelated to the disease (age, diabetes, dyslipidemia, obesity, prior cardiovascular diseases), related to the disease (cardiac AL-amyloidosis, hyperviscosity, high-output failure, arteriovenous shunting, anemia, renal dysfunction) and linked to antimyeloma treatment (anthracyclines, corticosteroids, alkylating agents, immunomodulatory drugs, proteasome inhibitors). An accurate knowledge of cardiovascular events, effective dose reductions, prevention and management of early and late cardiovascular side effects of chemotherapeutic agents are essential in current clinical practice. Myeloma experts are obliged to carefully balance drugs' efficacy and toxicity for each individual patient. This review summarizes current data and novel insights on cardiovascular adverse events of today's antimyeloma treatment, focusing on carfilzomib, which is the starting point to develop consensus recommendations on preventing and managing cardiovascular side effects in myeloma patients

Patient-centered practice in elderly myeloma patients: an overview and consensus from the European Myeloma Network (EMN)

Multiple myeloma is a disease typical of the elderly, and, because of the increase in life expectancy of the general population, its incidence is expected to grow in the future. Elderly patients represent a particular challenge due to their marked hete rogeneity. Many new and highly effective drugs have been introduced in the last few years, and resu lts from clinical trials are promising. Besides the availability of novel agents, a careful evaluation of elderly patients showed to be a key factor for the success of therapy. A geriatric assessment is a valid strategy to better stratify patients. In particular, different scores are available today to appropriately assess elderly patients and define their fitness/frailty status. The choice of treatm ent – transplantation, triplets, doublets, or reduced- dose therapies including novel agents – should depend on the patient’s fitness status (fit, intermediate-fit or frail). Second-generation no vel agents have also been evaluated as salvage therapy in the elderly, and these new agents certai nly represent a further step forward in the treatment armamentarium for elderly patients with multiple myeloma

An engineered, quantifiable in vitro model for analysing the effect of proteostasis-targeting drugs on tissue physical properties

Cellular function depends on the maintenance of protein homeostasis (proteostasis) by regulated protein degradation. Chronic dysregulation of proteostasis is associated with neurodegenerative and age-related diseases, and drugs targeting components of the protein degradation apparatus are increasingly used in cancer therapies. However, as chronic imbalances rather than loss of function mediate their pathogenesis, research models that allow for the study of the complex effects of drugs on tissue properties in proteostasis-associated diseases are almost completely lacking. Here, to determine the functional effects of impaired proteostatic fine-tuning, we applied a combination of materials science characterisation techniques to a cell-derived, in vitro model of bone-like tissue formation in which we pharmacologically perturbed protein degradation. We show that low-level inhibition of VCP/p97 and the proteasome, two major components of the degradation machinery, have remarkably different effects on the bone-like material that human bone-marrow derived mesenchymal stromal cells (hMSC) form in vitro. Specifically, whilst proteasome inhibition mildly enhances tissue formation, Raman spectroscopic, atomic force microscopy-based indentation, and electron microscopy imaging reveal that VCP/p97 inhibition induces the formation of bone-like tissue that is softer, contains less protein, appears to have more crystalline mineral, and may involve aberrant micro- and ultra-structural tissue organisation. These observations contrast with findings from conventional osteogenic assays that failed to identify any effect on mineralisation. Taken together, these data suggest that mild proteostatic impairment in hMSC alters the bone-like material they form in ways that could explain some pathologies associated with VCP/p97-related diseases. They also demonstrate the utility of quantitative materials science approaches for tackling long-standing questions in biology and medicine, and could form the basis for preclinical drug testing platforms to develop therapies for diseases stemming from perturbed proteostasis or for cancer therapies targeting protein degradation. Our findings may also have important implications for the field of tissue engineering, as the manufacture of cell-derived biomaterial scaffolds may need to consider proteostasis to effectively replicate native tissues

Melphalan 140mg/m2 or 200mg/m2 for autologous transplantation in myeloma: results from the Collaboration to Collect Autologous Transplant Outcomes in Lymphoma and Myeloma (CALM) study. A report by the EBMT Chronic Malignancies Working Party

Melphalan at a dose of 200mg/m2 is standard conditioning prior to autologous haematopoietic stem cell transplantation for multiple myeloma, but a dose of 140mg/m2 is often used in clinical practice in patients perceived to be at risk of excess toxicity. To determine if melphalan 200 and melphalan 140 are equally effective and tolerable in clinically relevant patient subgroups we analysed 1964 first single autologous transplantation episodes using a series of Cox proportional-hazards models. Overall survival, progression-free survival, cumulative incidence of relapse, non-relapse mortality, haematopoietic recovery and second primary malignancy rates were not significantly different between the melphalan 140 (n=245) and melphalan 200 (n=1719) groups. Multivariable subgroup analysis showed that disease status at transplantation interacted with overall survival, progression-free survival, and cumulative incidence of relapse, with a significant advantage associated with melphalan 200 in patients transplanted in less than partial response (adjusted hazard ratios for melphalan 200 versus melphalan 140: 0.5, 0.54, and 0.56). In contrast, transplantation in very good partial or complete response significantly favoured melphalan 140 for overall survival (adjusted hazard ratio: 2.02). Age, renal function, prior proteasome inhibitor treatment, gender, or Karnofsky score did not interact with overall/progression-free survival or relapse rate in the melphalan dose groups. There were no significant survival or relapse rate differences between melphalan 200 and melphalan 140 patients with high-risk or standard-risk chromosomal abnormalities. In conclusion, remission status at the time of transplantation may favour melphalan 200 or melphalan 140 for key transplant outcomes (NCT01362972)

In vivo Bioimaging as a Novel Strategy to Detect Doxorubicin-Induced Damage to Gonadal Blood Vessels

INTRODUCTION: Chemotherapy may induce deleterious effects in normal tissues, leading to organ damage. Direct vascular injury is the least characterized side effect. Our aim was to establish a real-time, in vivo molecular imaging platform for evaluating the potential vascular toxicity of doxorubicin in mice. METHODS: Mice gonads served as reference organs. Mouse ovarian or testicular blood volume and femoral arterial blood flow were measured in real-time during and after doxorubicin (8 mg/kg intravenously) or paclitaxel (1.2 mg/kg) administration. Ovarian blood volume was imaged by ultrasound biomicroscopy (Vevo2100) with microbubbles as a contrast agent whereas testicular blood volume and blood flow as well as femoral arterial blood flow was imaged by pulse wave Doppler ultrasound. Visualization of ovarian and femoral microvasculature was obtained by fluorescence optical imaging system, equipped with a confocal fiber microscope (Cell-viZio). RESULTS: Using microbubbles as a contrast agent revealed a 33% (P<0.01) decrease in ovarian blood volume already 3 minutes after doxorubicin injection. Doppler ultrasound depicted the same phenomenon in testicular blood volume and blood flow. The femoral arterial blood flow was impaired in the same fashion. Cell-viZio imaging depicted a pattern of vessels' injury at around the same time after doxorubicin injection: the wall of the blood vessels became irregular and the fluorescence signal displayed in the small vessels was gradually diminished. Paclitaxel had no vascular effect. CONCLUSION: We have established a platform of innovative high-resolution molecular imaging, suitable for in vivo imaging of vessels' characteristics, arterial blood flow and organs blood volume that enable prolonged real-time detection of chemotherapy-induced effects in the same individuals. The acute reduction in gonadal and femoral blood flow and the impairment of the blood vessels wall may represent an acute universal doxorubicin-related vascular toxicity, an initial event in organ injury